2.2ghz, 128mb, 160gb would be fine.. as you say you'll only be using windows in parallels for the odd bit of this and that.. dont even install vista on it. no university would REQUIRE you have vista since most people dont have it and it will be like this for a few years. I'd install win2k or XP, which are less resource hogging OS's so that parallels would be more capable of doing what you're doing with it while you're doing everything else you'll be doing in OSX. if you want to install bootcamp too, I suggest putting XP on it too since its still a way more supported system. for instance, at my uni, the VPN servers are rejected by vista.. "checkpoint is working on this" but osx works fine. I assure you though, after using OSX for a while, you wont be impressed by windows. you wont want to see its GUI that just tries to look pretty. the only time you'll ever want to use windows is when you need to, and then it'll just be wham bam thank you mam. I'm talking from my own experience. this is my perspective and I dont care if anyone thinks I should think otherwise. I personally dont really enjoy using windows anymore.
thank you.
-ruZZ